Battery harvesting device and method

ABSTRACT

A battery harvesting device and methods are disclosed for powering a load with a plurality of standardised batteries of different battery chemistries, each of the standardised batteries having a battery output voltage lower than a nominal voltage. The harvester comprises a power bus for attachment to the load, at least one receptacle arranged into each of a plurality of clusters, each receptacle configured for receiving one of the standardised batteries, each cluster further comprising electronics comprising an input connected to the receptacle and an output connected to the power bus, and a DC-DC boost circuitry for raising a battery output voltage of a connected one of the standardised batteries, and a processor for controlling the electronics such that each of the outputs connected the power bus is maintained at the nominal voltage.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a Divisional of U.S. application Ser. No. 15/960,730filed on Apr. 24, 2018 which claims benefit of U.S. provisionalapplication Ser. No. 62/488,909 filed on Apr. 27, 2017. All documentsabove are incorporated herein in their entirely by reference.

FIELD OF THE INVENTION

The present invention relates to a battery harvesting device and system.In particular, the present invention relates to a device which powers abus at a nominal voltage using batteries of a variety of differentstandardized types.

BACKGROUND

The prior art discloses circuits for recovering energy from partiallyspent batteries, generally referred to as scavenger circuits. Onedrawback of such prior art devices is that they are limited torecovering energy from a single source voltage or battery type, therebygreatly limiting their use in the field. Another drawback is that therecovered energy can only be used to recharge batteries of a singlebattery, again thereby greatly limiting theft use in the field.

SUMMARY OF THE INVENTION

In order to address the above and other drawbacks there is provided abattery harvester for powering a load with a plurality of standardisedbatteries of different battery chemistries, each of the standardisedbatteries having a battery output voltage lower than a nominal voltage.The harvester comprises a power bus for attachment to the load, at leastone receptacle arranged into each of a plurality of clusters, eachreceptacle configured for receiving one of the standardised batteries,each cluster further comprising electronics comprising an inputconnected to the receptacle and an output connected to the power bus,and a DC-DC boost circuitry for raising a battery output voltage of aconnected one of the standardised batteries, and a processor forcontrolling the electronics such that each of the outputs connected thepower bus is maintained at the nominal voltage.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A provides an isometric view of a battery harvester in accordancewith an illustrative embodiment of the present invention;

FIG. 1B provides a reversed isometric view of a battery harvester inaccordance with an illustrative embodiment of the present invention;

FIG. 2 provides a perspective view of an underneath of a batteryharvester in accordance with an illustrative embodiment of the presentinvention;

FIG. 3 provides an end plan view of a battery harvester in accordancewith an illustrative embodiment of the present invention;

FIGS. 4A and 4B provide alternate views of a receptacle in accordancewith an illustrative embodiment of the present invention;

FIG. 5A provides a perspective view of a battery harvester with thehousing removed and in accordance with an illustrative embodiment of thepresent invention;

FIG. 5B provides a lowered perspective view of the battery harvestedwith the housing removed and in accordance with an illustrativeembodiment of the present invention;

FIG. 6 comprises a block diagram of the electronics of a batteryharvester in accordance with a first illustrative embodiment of thepresent invention;

FIG. 7 comprises a block diagram of the electronics of a batteryharvester in accordance with a second illustrative embodiment of thepresent invention; and

FIG. 8 provides a block diagram of internal power source selection inaccordance with an illustrative embodiment of the present invention.

DETAILED DESCRIPTION OF THE ILLUSTRATIVE EMBODIMENTS

Referring now to FIGS. 1A and 1B, a battery harvester, generallyreferred to using the reference numeral 10, and in accordance with anillustrative embodiment of the present invention will now be described.The battery harvester 10 comprises a housing 12 defining a first bay 14comprised of a plurality of receptacles 16 arranged in pairs. Eachreceptacle 16 is configured for illustratively receiving a single AAtype battery 18. The housing also comprises slots, or belt loops, forreceiving a belt or the like. Eyelets 20 may also be provided forreceiving cord or the like.

Still referring to FIGS. 1A and 1B, the battery harvester 10 isadvantageously in one embodiment dimensioned to arrive at an overallsize which fits snugly into a standard sized ammo pouch (not shown) andsuch that the harvester 10 can be easily transported by soldier (notshown) using his regular equipment.

Referring to FIG. 2, in a particular embodiment the body 12 may comprisea second bay 24 on a second side thereof and comprising a plurality ofreceptacles 26 each configured to receive a CR123 type battery 28.

Referring to FIG. 3 in addition to FIG. 2, as will be discussed in moredetail below, a pair of USB type receptacles 30 are provided and whichmay be used to power external devices from power harvested from thebatteries 18 and/or 28.

Referring to FIGS. 4A and 4B, each receptacle 16 comprises a batteryreceiving bed 32 shaped to generally receive a respective one of thebatteries 18 or 28 therein. An icon 34 indicating the appropriateorientation of the battery (not shown) can be molded into the bottom ofthe bed 32. Contacts 36, 38 are positioned at either end of thereceptacle 16 which, as will be discussed in more detail below, areelectrically connected to a printed circuit board (PCB) via a respectivecontact pin 40, 42. Cutouts 44 are provided in the receptacles tosimplify the extraction of a battery placed therein. An orientation pin46 is provided on the bottom side 48 of the receptacle 16 to ensure thatthe receptacle 16 is installed in the correct orientation duringassembly.

Referring now to FIGS. 5A and 5B, as discussed above, the AA receptacles16 are mounted on a first PCB 50. Similarly, the CR123 receptacles 26are mounted on a second PCB 52. The first PCB 50 and second PCB 52 areinterconnected during assembly via a plurality of mezzanine typeconnectors 54 thereby allowing data and power and the like to betransferred between boards. Each PCB 50, 52 comprises the electronicsnecessary for harvesting power from batteries positioned in theirrespective receptacles and according to a control strategy as will bedescribed in more detail below.

Referring now to FIG. 6 in addition to FIGS. 5A and 5B, in a firstembodiment electronics 56 are provided on respective PCB boards 50, 52to manage batteries received in one or other of the receptacles 16. ACentral Processing Unit (CPU) 58 is provided which receives input from acell (battery) monitoring electronics 60 as to the presence of a batteryin one or other of the receptacles 16 and as well as illustratively theoutput current, voltage and the like. The receptacles 16 are arrangedinto clusters 62, each cluster 62 comprising at least one receptacle 16.In a particular embodiment each cluster comprises two (2) receptacles.

Still referring to FIG. 6, for each cluster 62, the outputs 64 of eachof the receptacles 16 are fed, illustratively in parallel, into aselector switch 66, controlled by the CPU 58 according to software andconfiguration settings stored in memory (not shown). In this regard, theCPU comprises a Pulse Width Modulation (PWM) module 68 which generates aplurality of PWM output signals 70. Switch select logic 72 is alsoprovided for each cluster 62, controlled by the CPU 58 and whichprovides the requisite logic for driving the cluster switch 66 with thePWM output signals 70. The output of the switch 66 is input to a flybackDC-DC boost comprising a magnetic element 74 and a rectifier filter 76in order to boost the output of the various cells such that they achievea nominal overall output of, for example, 12 volts. A current voltagemonitor 78 is also provided to ensure that the output voltage on thepower bus 82 is maintained at the nominal bus voltage. The output of theswitch 66 is also fed back to the CPU via a boundary detect module 80 toaid in driving the switch select logic 72. The switching speed of thePWM output signals is illustratively relatively low (for example circa10 khz-100 khz).

Still referring to FIG. 6, the receptacles 16 of each cluster 62 areillustratively arranged with their outputs in parallel. Initially, for agiven cluster the open circuit voltage of each battery 18 placed in arespective receptacle 16 is evaluated and the battery with the highestvoltage discharged first. To reduce the effect one battery in a clustermay have on another, other batteries 18 in the cluster 62 are dischargedas the current voltage of those batteries already discharging reacheswithin a predetermined voltage of the open circuit voltage of a batteryto be discharged. This allows batteries of different chemistries to besafely discharged together. As the load increases on the output, thevoltage typically drops and in order to compensate and maintain theoutput voltage constant (illustratively at 12V), the duty cycle of thePWM can be increased thereby increasing the output current/voltage ofthe output of the flyback convertor. The CPU 58 controls all clusters asin 62 at the same time thereby unifying the control. In particular, theCPU 58 can provide an indication of those clusters 62 in which thebatteries are in need of replacement.

Still referring to FIG. 6, status indicators 84 such as LEDs areprovided and controlled by the CPU 58 for indicating the status of abattery in one or other of the receptacles 16, for example a status ofempty or the like. Additionally, the CPU can communicate with other CPUs(for example on a different interconnected PCB board or a second device10) via one of an inter cluster communication module 86 and acommunication bus 88 or an external interface 90. In this regard, andwith reference to FIG. 3, a multipin connector 92, such as a FischerMiniMax™ type connector, comprising a plurality of conductive pins 94for interconnecting with the power bus 82 and communications bus 88using an appropriate cable (not shown) can be provided and such thatboth power and data can be shared between the device 10 and one or moreother like devices.

Referring now to FIG. 7 in addition to FIGS. 5A and 5B, in a secondembodiment, and similar to the first embodiment of FIG. 6, electronics56 are provided on respective PCB boards 50, 52 to manage batteriesreceived in one or other of the receptacles 16. The CPU 58 receivesinput from the monitoring electronics 60 as to the presence of a batteryin one or other of the receptacles 16. The receptacles 16 are arrangedinto clusters 62, each cluster 62 comprising at least one receptacle 16.

Still referring to FIG. 7, for each cluster 62, the outputs 64 of eachof the receptacles 16 are fed, illustratively in parallel, into adedicated one of at least one DC-DC Boost 96. Each DC-DC Boost 96 iscontrolled by the CPU 58 via control signals, illustratively transmittedfrom the CPU 58 to each DC-DC Boost 98 via a control bus 100 or thelike, and according to software and configuration settings stored inmemory (not shown). In this regard, each DC-DC Boost 98 may comprise aPulse Width Modulation (PWM) module (not shown) amongst other modules onan integrated circuit (also not shown). The output of each DC-DC Boost98 is fed at a nominal voltage, for example 12 volts, onto the outputpower bus 82 via a current monitor 96 which can also form part of thesame integrated circuit.

Still referring to FIG. 7, in the second embodiment, provided a batteryis present in a receptacle 16 the CPU 58, using control signalstransmitted via the control bus 100, is able to control the DC-DC Boost98 to deliver an output to the power bus 82 at the nominal voltage and aselected current. The value of the selected current can be adjusted inresponse to feedback received from the respective current monitors 96.For example, if the CPU 58 requests a given DC-DC boost 98 to deliver150 mA and the output cannot be sustained at the nominal voltage, thenthis can be detected via the current monitor 96 and adjusted by the CPU58 accordingly. Alternatively, the requested output current of a givenDC-DC boost 98 may be increased, for example in order to compensate forthe removal of batteries from one or other of the receptacles 16. Insome cases the DC-DC boost 98 may be commanded to cycle on and off inorder to extract a maximum of energy form a battery being harvested.

Still referring to FIG. 7, status indicators 84 such as LEDs areprovided and controlled by the CPU 58 for indicating the status of abattery in one or other of the receptacles 16.

Referring now to FIG. 8, of note is that power to operate the CPU 58 andother electronics is provided by batteries held in one or other of thereceptacles 16. In this regard, during normal operation batteries heldin any of the receptacles 16 can be used to power the CPU 58 and otherelectronics. At start up, however, and in order to simplify theelectronics, a designated first, or boot cell, cluster 104 providespower to the CPU 58 and other electronics via an internal power sourceselector 106 and a hold in capacitor 108. Once the CPU 58 has beenpowered up, the internal power source selector 106 can used to feed theinternal power supply with a different source such as the 12V power bus82. In this regard, a DC-DC buck converter 110 is used to reduce thepower bus voltage to one which is suitable for powering the CPU 58 andother electronics, typically between 3V and 5V. Additionally, a DC-DCconvertor 112 is provided to adjust the output voltage of the power bus82 such that it conforms to the USB standard and be used to providepower to the USB 5V out 114.

Although the present invention has been described hereinabove by way ofspecific embodiments thereof, it can be modified, without departing fromthe spirit and nature of the subject invention as defined in the claims.

We claim:
 1. A battery harvester for powering a load with a plurality ofstandardised batteries of different battery chemistries, each of thestandardised batteries having a battery output voltage lower than anominal voltage, the harvester comprising: a power bus for attachment tothe load; at least one receptacle arranged into each of a plurality ofclusters, each receptacle configured for receiving one of thestandardised batteries, each cluster further comprising electronicscomprising an input connected to said receptacle and an output connectedto said power bus, and a DC-DC boost circuitry for raising a batteryoutput voltage of a connected one of the standardised batteries; and aprocessor for controlling said electronics such that each of saidoutputs connected said power bus is maintained at the nominal voltage.2. The battery harvester of claim 1, wherein under control of theprocessor said circuitry limits an output current of the connectedstandardised battery.
 3. The battery harvester of claim 1, wherein inoperation said processor is powered said plurality of batteries via saidpower bus.
 4. The battery harvester of claim 1, wherein DC-DC boostcircuitry comprises a flyback DC-DC boost.
 5. The battery harvester ofclaim 4, wherein for each cluster the preferred one of the clusterbatteries is selected by monitoring an open circuit voltage of each ofthe cluster batteries and selecting one of the cluster batteries havingthe highest open circuit voltage.
 6. The battery harvester of claim 4,further comprising a PWM module generating a plurality of PWM outputsignals wherein each of said PWM output signals is input to a respectiveone of said flyback DC-DC boost.
 7. The battery harvester of claim 6,wherein said processor is further for monitoring an output of each ofsaid flyback DC-DC boost and accordingly adjusting a duty cycle of eachof said PWM output signals to maintain said flyback DC-DC boost outputsat said predetermined output voltage.
 8. The battery harvester of claim1, further comprising a USB port attached to said power bus via a DC-DCconvertor and configured for attachment to a USB port of the externaldevice for powering the external device.
 9. The battery harvester ofclaim 1, wherein each of said clusters comprises two receptacles. 10.The battery harvester of claim 1, further comprising electronics todetect the presence of a battery in any of said receptacles.
 11. Thebattery harvester of claim 1, wherein said predetermined output voltageis a nominal 12 volts.